The present invention relates to torque intensifying tools.
Torque intensifying tools may have several different applications in several different fields. One typical field of application relates to industrial torque wrenches for the fastening and loosening of nuts and bolts.
When torque intensifying tool is used in connection with the fastening or loosening of industrial nuts or bolts, the torque intensifying tool typically will have at least two modes of operation. In a first mode of operation the torque intensifying tool will operate with a high speed and a low torque. This is normally accomplished by deactivating some of the multiple gear cages within the tool. A second mode of operation will take place when the torque intensifying tool operates with a low speed but a high torque. This is normally accomplished when all gear cages are rendered operational.
In bolting applications, the high speed/low torque mode is used, for example, to run down a bolt until it is fully inserted into an object and its head abuts the object to which it is to be affixed.
The low speed/high torque mode is then used in the final operation of tightening the bolt in the object wherein higher torque and lower speed is required.
At high speed/low torque, the torque intensifying tool creates a reaction force which is transmitted to the handle, held by the operator, connected to the tool housing. The reaction force is relatively low and will normally be absorbed by the operator holding the handle.
Accordingly, a tool operator may normally be able to hold the tool handle provided that the handle is not subject a torque in excess of 5 ft. lbs. This means that in the tool, in which the torque intensifying means may create a torque of up to 50 in. lbs at the high speed the operator holding the handle can stop the housing from rotation.
In the second mode of operation when the torque intensifying tool is operated with a high speed/low torque, the handle of the tool is typically switched from a perpendicular position relative to the housing to a position corresponding to the general direction of the housing, to abut against a stationary object and thereby to stop the housing from turning in the opposite direction to the active force of the tool.
In a high speed/low torque mode of operation the handle must be held in its perpendicular position relative to housing in a stationary manner by the operator, so as not to permit the housing to rotate at high speed. In such operation the inertia created by the weight of the arm and the speed could injure the operator if the operator's hands were to be in the way of handle rotation.
One improvement of the subject invention is to provide for at least two modes of operation, one high speed/low torque and one low speed/high torque, in which it is assured that while the tool is used at high speeds/low torque, operator injury as a result of twisting the arm or moving parts at high speed or hitting against the stationary object can be avoided.